Both sitcoms are set to premiere on September 25, but you can watch them now if you're eager. I like both of them but "Ben and Kate" is my favorite. It's about a grown-up brother and sister duo (plus Kate's little girl) just figuring out their lives (Nat Faxon, who plays Ben, is hilarious with Maggie Jones, the young actress from "We Bought a Zoo," who plays Kate's little girl). In "The Mindy Project," Mindy Kaling (Kelly from "The Office") plays a single obstetrician looking for love.
I'll have more on both shows closer to their debut dates, but they're worth checking out (click titles above) if you don't want to wait for September 25.